[PT] Preparing a Polyester Producer

Rather than build a new floating production facility to develop its Gomez field in the deepwater Gulf of Mexico, ATP Oil & Gas is making plans to instead upgrade the Rowan Midland semisubmersible drilling rig and moor it on location as a production facility. InterMoor’s Todd Veselis and ATP’s Robert Shivers discuss the station-keeping details involved in what will be the region’s third application of permanent polyester system.

Offshore Engineer, May 2005

As Gomez is a small US Gulf of Mexico field located in approximately 3000ft of water on Mississippi Canyon block 311 with an expected life of three to 10 years, one key aspect of the project is the use of an existing mobile offshore drilling unit (MODU), the Rowan Midland semisub-Mexico field located in approx-mersible, as the production facility in an imately 3000ft of water on effort to minimize costs and make Mississippi Canyon block 311 with an development more economical. However, expected life of three to 10 years, one key regarding the mooring system of the aspect of the project is the use of an unit, this entailed several challenges.

For this portion of the job, ATP selected Acteon mooring company, InterMoor, to develop, procure and install a twelve, taut-leg polyester mooring system for the Rowan Midland using InterMoor’s suction embedded plate anchor (SEPLA) technology.

One of the challenges in the mooring design was to develop an efficient system which utilized as much of the Rowan Midland’s existing mooring equipment as possible including the rig’s eight mooring winches which are limited to 31/4in diameter wire. Due to this restriction, it was necessary to increase the number of mooring lines from eight to twelve whereby the additional four lines will utilize a chain segment at the fairlead as opposed to wire and tensioned with a chain jack and terminated in a chain stopper.